66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 23 



smaller ridges and very fine concentric striae. Interior of each valve with 

 about 28 radial ridges, smoothly angled in center of disk but sharply 

 angled and more prominent near ventral margin. Exterior of each valve 

 red-violet or purple-brown and with white markings; interior of right 

 valve ranging from purple to peach, left valve violet. 



Geographical range : Southern part of Gulf of California to Panama 

 Bay. 



Geochronological range: Reported only from the Recent. 



Bathy?netric range: Recorded in 17 to 182 fathoms. 



Ecological data: Found in sand, muddy sand, mud or rock bottoms; 

 associated with algae, coralline and coral. 



Hancock Expeditions Collecting Station : 

 GULF OF CALIFORNIA: Outer Gorda Bank; 59-64 fathoms, coral- 

 line, sand; sta. 1034-40. 



Genus CHLAMYS Roding 1798 



Chlamys Roding, 1798, p. 161. Type species: Pecten islandicus Miiller, 

 1776, p. 248 [designated type by Herrmannsen, 1846, p. 231], 

 type locality: "I. Horpudiskur . . . Island." Geographical range: 

 see Chlamys islandica, this paper. 



Zygochlamys von Ihering, 1907, p. 250. [Proposed as a subgenus of 

 Chlamys.] Type species: Pecten geminatus Sowerby, 1846, p. 252, 

 pi. 2, fig. 24; type locality: Patagonian formation (approximately 

 Lower Miocene) of San Julian, Argentina. 



Mimachlamys Iredale, 1929, pp. 162-163. Type species: Pecten asper- 

 rimus Lamarck, 1819, p. 174; type locality: "Habite les mers 

 australes, a la Nouvelle Hollande, les cotes de Diemen." 



Scaeochlamys Iredale, 1929, pp. 162-163. Type species: Pecten lividus 

 Lamarck, 1819, p. 178; type locality: "Habite les mers de la Nou- 

 velle Hollande, au port du Roi Georges." 



Belchlamys Iredale, 1929, p. 164. [Proposed as a subgenus of Scaeo- 

 chlamys.] Type species: Pecten aktinos Petterd, 1886, p. 320; type 

 locality : northwest coast of Tasmania. 



Coralichlamys Iredale, 1939, p. 355. Type species: Coralichlamys acro- 

 poricola Iredale, 1939, p. 356, pi. 5, figs. 26. 26a [= P. madre- 

 porarum Petit in Sowerby, 1842, p. 68, pi. 14, fig. 68; type locality: 

 Red Sea. Also found in the Indian Ocean, northern coast of Aus- 

 tralia, northern Queensland, and East Indies northward to Japan.] 

 Original diagnosis: None given by Roding. First diagnosis of genus 



in restricted sense presented by Cossman & Peyrot, 1914, p. 110: 



